Push-button switch mechanism for telephones.



PATENTED NOV. 14, 1905.-

BQL. LAWTON. PUSH BUTTON SWITCH MECHANISM FOR TELEPHONBS.

APPLIOATIOF FILED DEO.5,1904.

2 SHEETS-SHEET 1.

PAT-ENTED NOV. 14, 1905.

- B. L. LAWTON. PUSH BUTTON SWITCH MECHANISM FOR TELBPHONES.

APPLICATION FILED DEO.6,1904.

2 SHEETS-SHEET 2,

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UNITED STATES PATENT OFFICE.

BURTON LEONARD LAVVTON, OF MERIDEN, OONNEOTIOU", ASSIGNOR TO THE CONN. TELEPHONE AND ELECTRIC CO. OF MERIDEN, CONNECTI- OUT, A CORPORATION.

PUSH-BUTTON SWITCH MECHANISM FOR TELEPHONES.

Specification of Letters Patent.

Patented Nov. 14, 1905.

Application filed December 5, 1904. Serial No. 235,448.

To ctZZ whom, it may concern:

Be it known that I, BURTON LEONARD LAW- TON, a citizen of the United States, residing at Meriden, in the county of New Haven and 5 State of Connecticut, have invented a new and useful Improvement in Push Button Switch Mechanisms for Telephones; and [do hereby declare the following, when taken in connection with the accompanying drawings and the numerals of reference marked thereon, to be a full, clear, and exact description of the same, and which said drawings constitute part of this specification, and represent, in

Figure 1, a perspective view, on a reduced scale, of a push-button switch mechanism constructed in accordance with my invention; Fig. 2, a plan view of the mechanism with the cover removed; Fig. 3, a detached view, in side elevation, of the switch-block; Fig. 4, a reverse plan view thereof with the brackets at its ends shown in section; Fig. 5, a broken view thereof, in vertical longitudinal section, on the line a Z) of Fig. 4; Fig. 6, a view thereof in transverse section on the line (Z of Fig. 4.

My invention relates to an improvementin switch mechanisms for telephones, the object being to produce a simple, compact, and reliable push-button switch mechanism for intercommunicating telephones or kindred uses.

With these ends in view my invention consists in certain details of construction and combinations of parts, as will be hereinafter described, and pointed out in the claims.

As shown in Figs. 1 to 6, inclusive, I have applied my invention to the construction of a switch mechanism for adesk-telephone forming one of an installation of eleven corresponding instruments. This mechanism comprises a box 2, adapted to be secured by hooks 3 and eyes 4 to a base 5, which is solidly attached to the top of a desk. The top of the box is furnished with an escuteheon 6, having ten push-button holes 7 symmetrically arranged in rows of five holes each. As shown, the top of the box is also furnished with a directory-plate 8 for the reception of a card containing the desired reading matter. The base is formed with a cable-hole 9, through which the cable is led to the interior of the box 2, the cable not being shown. In the base I mount five binding-posts l0 1 10 10 locate an ordinary induction-coil 12, a call mechanism 13, and a resistance-coil 14. The features thus far described may, be of any approved construction and arrangement. Above the surface of the said base 5 I suspend a switch-block 15, formed of hard rubber or other equivalent insulating material and secured by screws 16 entering its ends to and between two corresponding brackets 17, having their lower ends bent inward to form feet which rest upon the said base 5, to which they are secured by screws, (not shown,) but passing upward through the base 5 from the lower face thereof into screw holes 17, formed in the said feet. The said block 15 is formed with ten holes 18, arranged in two series of five holes each and furnished near their lower ends with bushings or thimbles 19. These bushings 19 respectively receive composite plunger-like push-buttons, ten in number and all alike. Each of these pushbuttons consists, as shown, of a cap or top 20, made by preference of rubber and having a threaded longitudinal bore 20 adapting it to be applied to the threaded upper end of a plunger-stem 21, which also carries a shortinternally-threaded cylindrical metal body 22, upon which the lower end of the cap 20 bears, the said cap and body taking the wear of the operation of the push-buttons in the thimbles 19.

The body 22 is made removable for the application to the stem 21 of a contact-bushing 23 and of a spiral operating-spring 24, which latter encircles the plunger-stem and is interposed between the bushing 23 and the lower end of the said body 22. The metal bodies 22 and the springs 24 of the push-buttons secure for the bushings 23 and the contactspond to the push-buttons.

buttons 25 what is known as a spring-contact (necessary in telephone work) as distinguished from a sliding contact. The contact would be a simple sliding contact if it were not for the springs which make a positive contact and the metal bodies 22, which are virtually a part of the stems 21 carrying the contact-buttons 25. The lower portion of each plunger-stem is formed with a cone-like locking-button 25 and a washer-like contactbutton 26, located below the same, the eX- treme lower end of the stem forming a contact-tip 27 for engagement with the ringingplate 28, which is applied to the base 5 at a pointdirectly under the block 15 and between the brackets 17 and is located in the ordinary ringing-circuit. The said contact-bushing 23 forms a bearing for the lower end of the plunger-stem 21, an abutment for the lower end of the operating-spring 24, a stop coacting with the locking-button 25 to limit the upward movement of the plunger, and also an electric connection to the plunger, as will now be described. The stems 21 of the respective plungers pass downward through the said bushings 23,which are located near the lower ends of the holes 18 in the switch-block 15 and secured in place by means of contactscrews 29, passing through the lower ends of strap-like binding-posts 30, the upper ends of which are bent outward at a right angle to form lugs 31 for the reception of bindingscrews 32, to which the line-wires run. There are ten of these strap-like binding-posts 30 and ten of these binding-screws 32 to corre- To the sides of the switch block 15 I apply ten contactsprings 33-five on each side-arranged between the said binding-posts 30 and secured to the block by means of screws 34. The lower ends of these springs depend below the lower face of the switch-block 15 and are curved into position to be engaged by the washerlike contact-buttons 26 of the push-buttons when the same are in their intermediate depressed positions, as will be hereinafter described. The upper ends of the said contactsprings 33 are connected together by a common wire 35, let into a horizontal groove 36 in the side walls of the switch-block 15, this wire being connected at its forward end to a horizontal strap-like binding-post 37, secured to the forward end of the block 15 by means of a screw 38 and apin 38, and atits outer end bent to form an arm 39, receiving a binding-screw 40, to which one end of the wire 41 of the resistance-coil 14 leads.

For the purpose of holding any one of the push-buttons in its intermediate depressed position I employ a reciprocating locking-plate 42,bearing against the lower face of the switchblock 15, to which it is secured so as to be longitudinally movable by means, as shown, of four retaining-screws 43, passing through aeorrespondingnumber of elongated slots 42*,

formed in the plate. This plate 42 is formed with ten holes 44, each a little larger than the locking-buttons 25 of the push-buttons and arranged in conformity with the arrangement of the same. At one end the said plate is furnished with an arm 45, standing at a right angle to it and carrying a stud 46, which projects outward through the adjacent bracket 17, the projecting outer end of the stud 46 being furnished with a head or anvil 47, between which and the outer face of the said bracket I locate a light coiled spring 48, sufficient in power to move the plate 42 longitudinally into its normal position. Under this construction when any one of the push-buttons is pressed downward its cone-like locking-button 25 will be engaged with the wall of its complementary hole 44 in the locking-plate 42, whereby the plate will be moved longitudinally to permit the passage downward through the hole of the button, which is normally out of alinemcnt with the hole. Just as soon, however, as the top of the button has passsed entirely through the hole the said spring 48 will act to return the locking-plate into its normal position, so that when the spring 24 of the push-button acts to restore the same to its normal position a portion of the upper face of the locking-but ton 25 will be engaged with thelower face of the locking-plate at a point on one side of the 9 hole, whereby the plate acts to lock the pushbutton in question in its intermediate depressed position. at which time its washer-like contact-button 26 is engaged with its complementary contact-spring 33. blow in case any other push-button is depressed its cone-like locking-button 25 will operate the lockingplate 42 to aline its holes 44 with the lockingbuttons 25 of the push-buttons, so that the previously-locked push-button will be immediately released. At the same time the pushbutton just depressed will be locked in its intermediate depressed position, and so on. If two or more push-buttons are simultaneously depressed, they will be simultaneously locked in the same manner, and if two or more buttons are locked they will be simultaneously released the neXt time one or more buttons are depressed. It will be seen, however, that when the -push-buttons are manually released one button will ofnecessity be depressed and locked in its intermediate position by the lockingplate. In order to operate the locking-plate to release this button, so as to restore the instrument to its full normal condition, I employ means independent of all of the buttons for automatically operating the locking-plate to release the push-button or push-buttons that may be locked in their intermediate positions at the end of the last preceding use of the device. For this purpose I employ a hammer 49, arranged to strike light blows upon the anvil 47 aforesaid and carried by an arm 50, forming an extension of the armature 51 of the call mechanism l3. The hammer 49 does not effect the unlocking movement of the locking-plate 42 by a single blow, but by a series of blows each of which moves the plate a trifle until it has been moved sufliciently to release the push-button or push-buttons engaged with it, after which the plate is returned to its normal position by its spring 48. Of course if the magnet of the call mechanism 13 is a strong magnet one blow of the hammer might be enough to unlock the plate. It is obvious, however, that instead of utilizing the call mechanism 13 to operate the locking-plate 42 in the manner described I might employ an independent magnet arranged to operate the plate by one or more blows. It will be understood that when the plate is moved by a series of blows every advance, however minute, made by the plate is held by the friction between it and the locking button or buttons engaged with it. The said spring, it may be explained, is not strong enough to prevent the cumulative action of the hammer 49, as described above, but only strong enough to move thelocking-plate 42 when all of the pushbuttons are in their released positions.

I have described the contact-springs 33 as being connected together by a common wire 35. In the construction shown, however, one of these springs, which for convenience I will specially designate 33, is not connected with the wire 35, but connected by a wire 52 with a local release-battery 55 of ordinary construction. A spring 53, Fig. 3, secured to the adjacent end of the switch-block 15, has its lower end arranged to be engaged by the contact-button 26 of the push-button coacting with the spring 33 at the same time that the said spring 33 is engaged by the said button. The spring 53 is connected by a wire 54 to the binding-post 11, Fig. 2, which is connected, as before explained, with the home-station wire. It should now be explained that the particular push-button which coacts with the contact-spring 33 and the spring 53 is the button which is employed to establish a connection with the city exchange or any manual exchange. As the current used to call from the manual exchange is too weak to operate the magnet of the call mechanism 13 so as to effect the magnetic hammer movement of the locking-plate into its unlocked position, I employ in the manner described the spring 53, which is located in the circuit of the local release-battery 55, whereby an extra current is brought into play for effecting the unlocking movement of the locking-plate.

For clearness and convenience I have shown the local release-battery 55 and the circuit thereof in conjunction with Fig. 2. In this figure the wire 54 aforesaid is shown as leading from the spring 53 (which might aptly be termed the local release-circuit spring) to the binding-post 11"; but the connection of the spring 53 with the binding-post 11 is for other purposes than for the energizing of the call mechanism 13. A wire 56, connected with the said wire 54, leads thence to one side of the call mechanism 13, the other side of which is connected by a wire 57 to the binding post 10, which in turn is connected, through the desk-telephone, which is not shown but which is of ordinary construction, to the binding-post 10 which is connected by a wire 58 with the local release-battery 55, which is in turn connected by the wire 52, before mentioned, with the spring 33. It will be now clearly understood that when the springs 33 and 53 are brought into contact by the depression of their complementary push-button a circuit is closed through the local release-battery 55, which is thus thrown onto the call mechanism 13, the energization of which causes the hammer 49 to vibrate and efiect the unlocking movement of the locking-plate 42, whereby the particular pushbutton now being considered is released.

The operation of the mechanism with re-.

gard to the feature just described is as follows: To talk with the city exchange or any manual exchange, the telephone-receiver is first removed from the desk-telephone, whereby the circuit between the binding-post 10 and 10 is broken. The particular push-button coacting with the spring 33 and the special local release-battery spring 53 is then depressed and is at once engaged in its clepressed position and held therein by the locking-plate 42. Now after the use of the telephone the receiver thereof is restored to its book, whereby the binding-posts 10 and 10 are again connected and a circuit completed through the local release-battery 55, through the call mechanism 13 and through the springs 33 and 53. The battery 55 now being cut into the call mechanism 13, the same is energized with sufficient power to operate the hammer 49 and automatically release the particular push-button referred to.

In view of the modifications suggested and of others which may obviously be made I would have it understood that I do not limit myself to the particular construction herein shown, but hold myself at liberty to make such changes and alterations as fairly fall within the spirit and scope of my invention.

Having fully described my invention, what I claim as new, and desire to secure by Letters Patent, is-

1. In a push-button switch mechanism, the combination with a series of push-buttons, of a locking instrumentality for locking any one or more of the said buttons in their depressed or operating positions, and electrically-operated means for operating the said locking instrumentality in releasing any one or more of the buttons and so restoring the apparatus to normal.

2. The combination with a series of pushbuttons, of a locking-plate for lockingany one or more of the said buttons in their depressed or operating positions, and electrically-operated means for moving the said locking-plate to cause it to release any button or buttons held in a depressed position by it.

3. In a push-button switch mechanism, the combination with a series of push-buttons, of a locking instrumentality for locking any one or more of them in depressed or operated position, and an electrically-operating hammer for operating the said instrumentality in releasing any of the buttons held by it in depressed or operating position.

a. In a push-button switch mechanism, the combination with a series of push-buttons, of a locking-plate for holding any one or more of them in their depressed positions, and an electrically-operated hammer operating upon the plate to move it to release any button or buttons held in depressed position by it.

5. In a push-button switch mechanism, the combination with a switch-block formed with holes, of insulated contact-bushings located within the said block at or near the lower ends of the said holes, push-buttons located in the said holes and having their stems passed through the respective contact-bushings, contact-springs coacting with the respective pushbuttons, and means for locking any one or more of the push-buttons in their depressed or operating positions in which they coact with the said contact-springs and for releasing the said buttons from their depressed positions.

6. In a push-button switch mechanism, the combination with a switch-block having holes, of insulated contact-bushings located within the said block at or near the lower ends of the said holes, push-buttons the stems whereof pass through the said bushings and carry lockingbuttons and contactbuttons, contactsprings for direct electrical engagement by the said contact-buttons, and a movable locking instrumentality coacting with the locking-buttons for holding the push-buttons in their depressed positions.

7. In a push-button switch mechanism, the combination with a switch-block having holes, of insulated contact-bushings located within the said block at or near the lower ends of the said holes, push-buttons the stems of which pass through the said bushings, contact-buttons located upon the projecting ends of the said stems,contact-springs for direct electrical engagement with the contact buttons, and means for locking the push-buttons in their depressed or operating positions.

8. In a push-button mechanism, the combination with a switch-block, of-a series of pushbuttons mounted therein, a series of contactsprings for engagement by the said buttons, a locking instrumentality coacting with all of the buttons for locking them in their depressed or operating positions in vhich they are held in contact with their complementary contactsprings, and a contact-spring located in the circuit of the local release-battery and arranged for being engaged by one of the pushbuttons at the same time the same is engaged with its complementary contact-spring.

9. In a push-button switch mechanism, the combination withaswitch-block, of a series of push-buttons mounted therein and each having a locking-button and a contact-button, of a series of complementary contact-springs arranged to be engaged by the contact-buttons of the push-buttons, a movable locking-plate coacting with the locking-buttons of the pushbuttons for holding the same in their depressed positions in which they are engaged with their complementary contact-springs, electrically-operated means for moving the said plate to release any one or more of the push-buttons after depression, and a spring located in the local release-circuit and arranged to be engaged by the contact-button of one of the push-buttons when the contactbutton thereof is engaged with its complementary contact-spring.

10. In a push-button switch mechanism, the combination with aswitch-block having holes, of insulated contact-bushings located within the said block at or near the inner ends of the said holes, push-buttons the stems of which pass through the said bushings, contactsprings for direct electrical engagement by the said buttons, and a locking instrumentality coacting with all of the push-buttons for locking them in their depressed or operating positions in which they are held in contact with their complementary contact-springs.

11. In a push-button switch mechanism for telephones, the combination with a switchblock, of a series of push-buttons mounted therein and each comprising a stem, a spring,

a locking-button and a contact-button located below the same close to the lower end of the stem; a series of contact-bushings mounted in the said switch-block in position to have the stems of the push-buttons pass through them, a series of contact-springs arranged in position to coact with the contact-buttons of the push-buttons, and a movable locking instrumentality coacting with the locking-buttons of the push-buttons for holding the same in their depressed positions in which they are engaged with the said contact-springs, and an electrically-operated means for moving the said instrumentality to release any one or more of the said push-buttons after depression.

12. In a push-button switch mechanism, the combination with a switch-block having holes, of insulated contact-bushings located within the block at or near the lower ends of the said holes, push-buttons each having a cylindrical metal body corresponding in diameter to the said holes, a stem carried by the said body, and a spring encircling the stem, the stems of the respective push-buttons passing tl'irough the said contact-bushings, and the springs of the respective push-buttons being located Within the said holes and encircling the said stems, contact-springs for direct electrical engagement by the said buttons, and a movable locking instrumentality coacting With the push-buttons for holding the same in their depressed positions.

In testimony whereof I have signed this specification in the presence of two subscribing Witnesses.

BURTON LEONARD LAVVTON.

Witnesses:

B. 0. ROGERS, E. C. WILCOX. 

